A vibration actuator utilizes expansions and contractions of a piezoelectric body to generate progressive oscillation waves at a driving surface of an elastic body. Elliptical motions are generated at the driving surface by the progressive waves, and a moving element that is in pressure contact with wave peaks of the elliptical motions is driven (see Patent Document 1). This vibration actuator is characterized by having high torque even at low speeds of rotation. Therefore, when it is mounted in a driving device, there are benefits in that gears may be omitted, gear noise is eliminated, and positioning accuracy may be improved.
Patent Document 1: Examined Patent Application Publication H01-17354